Looper-thread-controlling mechanism



Nov. a, 1925- ,559,568

G. 5. GATCHELL' LOOP-ER THREAD CONTROLLING MECHANISM med March 27; 1922 2 Sheets-Sheet .L

INVENTOR (5. s. GATCHELL:

LOOPER THREAD CONTROLLING MECHANISM Nov. 3 1925- 2 Sheets-Sheet 2 Filed March 27, 1922 as i k N ISQNTOR 4 wimssses; W 801%.

ATTORNEY Patented Nov. 3, 1925.

GEORGE S. GATCHELL, O'F ROSELLE PARK, NEW JERSEY, 'ASSIGNOB TO THE SINGER- y 1,559,558 narran stares PATENT OFFICE.

I'JIANUFACTURING COMPANY, OF ELIZABETH, JERSEY, A CORPORATION NEW JERSEY.

-LOOPER-THREAD-GONTROLLING MECHANISM.

, Application filed March 27, 1922- Serial No; 547,278.

To all whom it may concern.

Be it known that I, Gnonen S. GATCHELL, a citizen of the United States, residing at Roselle Park, in the county of Union and- State of New Jersey, have invented certain new and useful Improvements in Looper- Thread-Controlling Mechanisms, of which the following is a specification, reference being had therein to the accompanying drawings.

This invention relates to looper-thread controller mechanism for chain-stitch sewing machines and has for an object to pro-- vide a 'toand-fro moving or oscillatory thread-controller having operative characteristics approximating those of looperthread controllers ofthe rotary type, thus affording satisfactory control of the looperthread in machines having an oscillatory thread-controlling shaft, without the necessity of altering the driving mechanism for such shaft or changing the position of such shaft in the machine frame.

Looper-thread controllers of the type under consideration commonly comprise an intermittent V-looper-thread nipper, a take-up cam on the looper side of suchnipper and a pull-off cam on the thread-supply side of such nipper. The take-up cam serves to control the slack in the looper-thread during the retraction of the looper-bladeand to pay out looper-thread as the looper advances. The pull-off cam serves to provide afree supply of looper-thread for easy passage through the thread-nipper. It is customary. to time the thread-nipper to hold the looper-thread as the looper-thread take-up pulls back the slack given up by the retracting looper, and to release the thread as the looper advances, thus permittingthe latter to pull thread from the supply. Hereto fore, in thread-controlling mechanism of the oscillatory type, the cam for closing the nipper during the retraction of the looper has also necessarily operated to close the nipper during the advance of the looper. This double closing of the nipper by the oscillatory nipper-cam is undesirable as, for best results, the looper-thread should be free to run through the nipper during the advance of the looper.

According to the present improvement, the nipper-operating cam has been reconstructed to operate when its shaft rocks in one direction and to be ineffective when its shaft rocks in the reverse direction; the

result being, that the nipper is closed but once during each stitch-forming cycle,;i. e., during the retract on of the looper, and remains open during the entire advancing stroke of the looper. p r

In the accompanying drawings, Fig. 1 is a fragmentary side elevation, partly in secinclusive, illustrate the pull-off, thread-nipper, take-up and stitch-forming instrumentalities in their respective positions when the loopers are beginning their retracting stroke. Figs. 4 to 4 inclusive, are similar views at a slightly later period in the cycle when the nipper is closed. Figs. 5 to 5 are similar views at the period in the cycle when the loopers are beginning their ad vance stroke. Figs. 6 to 6? are similar views at the period in the cycle when the advancing loopers have passed safely into the needle-loops. Fig. 7 is a diagram showing the action of the various thread-controlling instrumentalities on the thread at diiferent periods in the cycle and Fig. 8 is a transverse sectional view through the nipper operating cam. 1 v i In the embodiment of the invention chosen for the purposes of the present disclosure 1 represents the standard of a cylinder-bed machine of the usual type represented 'in the patent to Molyneux No. 1,111,167. The

operating the needles 3 and loopers 4 in the usual manner to sew two separate rows of double-chain stitches. The loopers t are mounted on the rocking and endwise sliding looper-shaft 5 'which extends within and lengthwise of the cylinder-bed 6.

The looper-thread controlling mechanism is mounted on the usual rock-shaft 7 dis posed within and transvers of the cylinderbed 6 on the conical bearing pins 8. This shaft has fixed thereto a crank 9 which is connected by the pitman 10 to an actuating eccentric 11 on the main-shaft2. The takeup cam is preferably shaped substantially as shown in Fig. 3 and may comprise the twinblades 12 between and at the sides of which are arranged the three thread-guiding arms 25 are open.

13; a double cam of this nature having sub stantially double the action on the thread as compared with a single cam.

The pull-off cam is shown at 14 and acts on the thread between the thread-guiding arms 15. V

Mounted on the shaft 7 between the cams 12 and 14 is the nipper operating device comprising a collar 16 to which is pivotea at 17 the rocking toggle element or cam-section 18 preferably having fiat sides 19 and 20 adapted to contact respectively with the fiat tened surfaces 21 and 22 on the collar 16. The toggle element 18 is preferably formed with a curved side 23 which is substantially concentric with the shaft 7 when the element 18 isin one of its extreme positions with the surfaces 20 and 22 in contact, Fig. 4 The curved side 23 is high enough to lift the lower nipper-spring 2% into nipping relation with the upper nipper-spring 25.

The tilting element 18 is preferably formed with another curved side 26. which is substantially concentric with the shaft 7 when said element is in the other of its extreme positions, Figs. 3 or 5*, with the surfaces 19 and 21 in contact. The curved side 26 is not high enough to lift the lower spring 24 into nipping relation with the upper spring 25 and rides under the nipper springs, during the return movement of the rock shaft 7, Fig. 6, without closing such springs.

The curved sides 23 and 26 of the pivoted element 18 may meet to form an edge 27 which is so related to the spring 2% and to the centers of the pivot 1? and shaft 7 as to cause said element to be tilted from one extreme position to the other during the first part of the rocking movement of the shaft '1' in either direction; said edge 2? and pivotal center 1'? giving to the element 18 the character and function of a toggle element having a wiping engagement with the thread-nipper.

Referring to F igs. 3 to 3 inclusive, the needles 3 are fully raised and the loopers 1- are fully advanced. The nipper-springs The take-up and pull-off cams are out of engagement with the looperthread. As the loopers dwell in their advanced position, the shaft 7 rocks suiiiciently to tilt the toggle element or cam-section 18 from the position shown in Fig. 3 to that shown in Fig. 4, thus closing the nipper at about the time the takeup cam 12 and pulloff cam 14 engage the thread. As the loopers retract from the position shown in Fig. f n the nipper remains closed and the cam-edge 28 on the take-up cam 12 in cooperation with the thread-guides 13 absorbs the slack-thread given up by the looper. The cam lei pulls thread fro-m the supply. Before the loopers reach the end of their retracting stroke the thread slips over the hump 29 or high point on the cam 12 and slackis thus afforded to permit the loopers to move to the end of their retracting stroke. The nipper opens at about the time the thread slips over the hump '29. As the loopers execute the first part of their advancing stroke, Figs. 5 to 6, the cam-edge 30 on the take-up cam 12 pulls back on the looper-thread and prevents buckling of the thread in front of the eyes of the ioopers. When the loopers have passed safely into their respective needleloops, Fig. 6 the thread slips over the hump 29 on the take-up cam and is free to be drawn upon by the loopers in advancingto the ends oftheir strokes. It will be observed that the nipper remains open during the entire advance of the loopers. i

The looper-threads pass through the usual guide-eyes in the looper-blades, thence through the eye 31 in the heel of the looper nearer the end of the arm (3 and then through the usual thread-tube 32 to the thread-controlling devices on the shaft 7.

By the means described, the nipper is operated by an oscillatory shaft, yet is closed only during the retracting stroke of the loopers; the timing being similar to that obtained by the use of a rotary nipper operating shaft.

Having thus set forth the nature of the invention, what I claim herein is 1. In a sewing machine, an oscillatory shaft,a thread-nipper, and a nipper operating toggle element pivotally connected to said shaft and having a wiping engagement with said thread-nipper.

2. Ina sewing machine, in combination, a

thread-nipper, an oscillatory shaft, a nipper 7 operating element pivoted eccentrica-lly on and tiltably movable relative to said shaft, and means for limiting the tilting movement of said element.

3. In a sewing machine, in combination, a thread-nipper, an oscillatory shaft, and a nipper operating element pivoted eccentrically on said shaft for rocking movement between predetermined limits relative to the latter, said element being adapted to alternately assume effective and ineffective positions as said shaft oscillates.

4-. In a sewing machine, an oscillatory shaft, a thread-nipper, and a thread-nipper operating cam mounted on and movable relative to said shaft, said cam having high and low faces which act alternately upon said nipper to close the latter during the oscillation of said shaft in one direction only.

5. In a sewing machine, an oscillatory shaft, a thread-nipper, a. support secured to said shaft, a nipper-operating element pivotally mounted on said support, and means for limiting the range of pivotal movement of said element relative to said support.

6. In a sewing machine, an oscillatory shaft, a thread-nipper, a collar secured to said shaft, and a nipper operating cam having high and low faces and pivoted on said collar eccentrically of said shaft.

7. In a sewing machine, an oscillatory shaft, a thread-nipper, and a nipper-operating toggle element pivotally connected to said shaft, the center of said-pivotal connection passing back and forth between the nipper and the centerof said shaft.

8. In a sewing machine, an oscillatory 10 shaft, a thread-nipper, a collar secured to element pivoted on said collar eccentrically of said shaft, the center of said pivot passing back and forth between the nipper and the center of said shaft as the latter oscillates.

In testimony whereof, I have signed my name to this specification.

GEORGE s. GATCHELL. 

